We propose a continuation of our applications of molecular dynamics and free energy calculations to complex molecules on condensed phases, emphasizing applications to proteins, nucleic acids and ionophores. The goals of this research are to develop models that can correctly represent the structures and energetics of such systems and to apply these models to problems in ligand binding, protein and nucleic acid stability, enzyme catalysis and drug design. We also propose to continue to develop and optimize out AMBER software for use on both shared memory and message passing parallel computers.